Real-time safe services + clients

ros2 / rclcpp

rclcpp (ROS Client Library for C++)

Apache License 2.0

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Real-time safe services + clients #104

Open jacquelinekay opened 9 years ago

jacquelinekay commented 9 years ago

Make the client/service pipeline safe for real-time execution. It has not yet been vetted for allocations, STL structures which malloc automatically, and nondeterministic blocking.

This will be required for RT-safe node lifecycle, since we plan to use services to transition between states in the lifecycle.

[ ] abstract out "new" in Service::handle_request
[ ] abstract out make_shared from async_send_request
[ ] rt-safe alternatives to std::vector and std::map (maybe just use a custom allocator)
[ ] example with OS-specific threading abstraction (instead of std::future)
[ ] testing/profiling

BobDean commented 9 years ago

there are a couple of open items with out descriptions. If those could be populated, even with something simple, it would help understand what is being worked on but is not yet in the public repos.

gerkey commented 9 years ago

@BobDean: FYI, everything we're doing is in public repos, but perhaps on branches. But I take the point about having more descriptive tickets, as it gives more information about what remains to be done (which will hopefully make it easier for external contributors to pitch in).

BobDean commented 9 years ago

@gerkey my "public" comment was due to reading tickets which seemed to relate to something on the developers machine, which I did not see when browsing the github source. So maybe the ticket progress/resolution had not been pushed to github yet. Which is fine, that's how software development goes. The description would let me fill in the gap while browsing.

jacquelinekay commented 9 years ago

I have a branch abstracting out allocations in services and clients, but I'm blocked by an issue with allocations from within the stdlib (std::promise). I've asked it on Stack Overflow:

http://stackoverflow.com/questions/33638134/stdpromise-with-custom-allocator-appears-to-use-global-new

jacquelinekay commented 9 years ago

It turns out the issue with promise will be fixed in gcc 5. Unless it gets backported to gcc 4.8 or 4.9, that means we won't be able to use std::promise for RT services and clients until we start targeting 16.04.